This invention relates to vehicle axles and axle subassemblies, and particularly to trail arm twist beam axles and axle subassemblies.
A trail arm twist beam axle is intended to semi-isolate one wheel of a vehicle such as an automobile from the opposite wheel. Connection points are made to the body mounts, wheel spindles, shocks and springs, as well as to track bars for lateral stability. Individual component pieces typically making up an axle assembly include the twist beam, trail arms, flanges, spring supports, jounce bumpers, shock mounts, bushing mounts and torsion bar.
Various cross sectional configurations have been suggested for twist beam and torsion bar elements heretofore, although typically a twist beam comprises an inverted, U-shaped beam for bending loads, coupled with a separate solid torsion rod of different material and characteristics from those of the beam, and extending through the open central portion of the beam, for accommodating torsional loads. The U-shaped beam is normally a drawn or stamped member which is not strong in torsion. Both ends are attached to stubs extending in from the spring seats. The separate rod to control torsional loads is specially fabricated of a high strength steel. Its ends are attached separately from, and in a special relationship relative to, the ends of the beam. The material costs, manufacturing costs and assembly costs of the two-piece twist beam and torsion bar arrangement are significant.